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ACCESS(5)                                                            ACCESS(5)

NAME
       access - Postfix access table format

SYNOPSIS
       postmap /etc/postfix/access

       postmap -q "string" /etc/postfix/access

       postmap -q - /etc/postfix/access <inputfile

DESCRIPTION
       The  optional  access(5)  table  directs  the Postfix SMTP
       server to selectively reject or accept mail. Access can be
       allowed  or  denied for specific host names, domain names,
       networks, host addresses or mail addresses.

       For an example, see the EXAMPLE section at the end of this
       manual page.

       Normally,  the access(5) table is specified as a text file
       that serves as  input  to  the  postmap(1)  command.   The
       result,  an  indexed file in dbm or db format, is used for
       fast searching by the mail  system.  Execute  the  command
       "postmap  /etc/postfix/access"  in  order  to  rebuild the
       indexed file after changing the access table.

       When the table is provided via other means  such  as  NIS,
       LDAP  or  SQL,  the  same lookups are done as for ordinary
       indexed files.

       Alternatively, the table can be  provided  as  a  regular-
       expression map where patterns are given as regular expres-
       sions, or lookups can be directed to TCP-based server.  In
       that  case,  the  lookups are done in a slightly different
       way as described below under "REGULAR  EXPRESSION  TABLES"
       and "TCP-BASED TABLES".

CASE FOLDING
       The  search  string is folded to lowercase before database
       lookup. As of Postfix 2.3, the search string is  not  case
       folded  with database types such as regexp: or pcre: whose
       lookup fields can match both upper and lower case.

TABLE FORMAT
       The input format for the postmap(1) command is as follows:

       pattern action
              When pattern matches a mail address, domain or host
              address, perform the corresponding action.

       blank lines and comments
              Empty lines and whitespace-only lines are  ignored,
              as  are  lines whose first non-whitespace character
              is a `#'.

       multi-line text
              A logical line starts with non-whitespace  text.  A
              line  that starts with whitespace continues a logi-
              cal line.

EMAIL ADDRESS PATTERNS
       With lookups from indexed files such as DB or DBM, or from
       networked  tables  such  as NIS, LDAP or SQL, patterns are
       tried in the order as listed below:

       user@domain
              Matches the specified mail address.

       domain.tld
              Matches domain.tld as the domain part of  an  email
              address.

              The pattern domain.tld also matches subdomains, but
              only when the string smtpd_access_maps is listed in
              the  Postfix  parent_domain_matches_subdomains con-
              figuration setting (note that this is  the  default
              for  some versions of Postfix).  Otherwise, specify
              .domain.tld (note the  initial  dot)  in  order  to
              match subdomains.

       user@  Matches  all mail addresses with the specified user
              part.

       Note: lookup of the null sender address  is  not  possible
       with  some types of lookup table. By default, Postfix uses
       <> as the lookup key for  such  addresses.  The  value  is
       specified  with the smtpd_null_access_lookup_key parameter
       in the Postfix main.cf file.

EMAIL ADDRESS EXTENSION
       When a mail address localpart contains the optional recip-
       ient  delimiter  (e.g., user+foo@domain), the lookup order
       becomes: user+foo@domain, user@domain, domain,  user+foo@,
       and user@.

HOST NAME/ADDRESS PATTERNS
       With lookups from indexed files such as DB or DBM, or from
       networked tables such as NIS, LDAP or SQL,  the  following
       lookup patterns are examined in the order as listed:

       domain.tld
              Matches domain.tld.

              The pattern domain.tld also matches subdomains, but
              only when the string smtpd_access_maps is listed in
              the  Postfix  parent_domain_matches_subdomains con-
              figuration setting.  Otherwise, specify .domain.tld
              (note  the  initial  dot)  in order to match subdo-
              mains.

       net.work.addr.ess

       net.work.addr

       net.work

       net    Matches the specified IPv4 host address or  subnet-
              work.  An  IPv4  host address is a sequence of four
              decimal octets separated by ".".

              Subnetworks are matched  by  repeatedly  truncating
              the last ".octet" from the remote IPv4 host address
              string until a match is found in the access  table,
              or until further truncation is not possible.

              NOTE 1: The information in the access map should be
              in canonical form, with unnecessary null characters
              eliminated.    Address   information  must  not  be
              enclosed with "[]" characters.

              NOTE 2: use the cidr lookup table type  to  specify
              network/netmask  patterns.  See  cidr_table(5)  for
              details.

       net:work:addr:ess

       net:work:addr

       net:work

       net    Matches the specified IPv6 host address or  subnet-
              work.  An  IPv6 host address is a sequence of three
              to eight hexadecimal octet pairs separated by  ":".

              Subnetworks  are  matched  by repeatedly truncating
              the last ":octetpair" from  the  remote  IPv6  host
              address string until a match is found in the access
              table, or until further truncation is not possible.

              NOTE 1: the truncation and comparison are done with
              the string representation of the IPv6 host address.
              Thus, not all the ":" subnetworks will be tried.

              NOTE 2: The information in the access map should be
              in canonical form, with unnecessary null characters
              eliminated.    Address   information  must  not  be
              enclosed with "[]" characters.

              NOTE 3: use the cidr lookup table type  to  specify
              network/netmask  patterns.  See  cidr_table(5)  for
              details.

              IPv6 support is available in Postfix 2.2 and later.

ACCEPT ACTIONS
       OK     Accept the address etc. that matches the pattern.

       all-numerical
              An all-numerical result is treated as OK. This for-
              mat is generated by address-based relay  authoriza-
              tion schemes such as pop-before-smtp.

REJECT ACTIONS
       Postfix  version  2.3  and  later  support enhanced status
       codes as defined in RFC 3463.  When no code  is  specified
       at  the  beginning  of  the  text below, Postfix inserts a
       default enhanced status code of "5.7.1"  in  the  case  of
       reject  actions, and "4.7.1" in the case of defer actions.
       See "ENHANCED STATUS CODES" below.

       4NN text

       5NN text
              Reject the address etc. that matches  the  pattern,
              and respond with the numerical three-digit code and
              text. 4NN means "try again later", while 5NN  means
              "do not try again".

              The  reply  code "421" causes Postfix to disconnect
              immediately (Postfix version 2.3 and later).

       REJECT optional text...
              Reject the address etc. that matches  the  pattern.
              Reply  with  $reject_code optional text... when the
              optional text is specified, otherwise reply with  a
              generic error response message.

       DEFER_IF_REJECT optional text...
              Defer  the  request if some later restriction would
              result in a REJECT action. Reply with "450 optional
              text... when the optional text is specified, other-
              wise reply with a generic error response message.

              This feature is available in Postfix 2.1 and later.

       DEFER_IF_PERMIT optional text...
              Defer  the  request if some later restriction would
              result in a an explicit or implicit PERMIT  action.
              Reply  with "450 optional text... when the optional
              text is specified, otherwise reply with  a  generic
              error response message.

              This feature is available in Postfix 2.1 and later.

OTHER ACTIONS
       restriction...
              Apply the named UCE restriction(s) (permit, reject,
              reject_unauth_destination, and so on).

       DISCARD optional text...
              Claim  successful delivery and silently discard the
              message.  Log the optional text if specified,  oth-
              erwise log a generic message.

              Note:  this action currently affects all recipients
              of the message.   To  discard  only  one  recipient
              without  discarding  the  entire  message,  use the
              transport(5) table to direct mail to the discard(8)
              service.

              This feature is available in Postfix 2.0 and later.

       DUNNO  Pretend that the lookup key  was  not  found.  This
              prevents  Postfix  from  trying  substrings  of the
              lookup key (such as a subdomain name, or a  network
              address subnetwork).

              This feature is available in Postfix 2.0 and later.

       FILTER transport:destination
              After the message is queued, send the  entire  mes-
              sage through the specified external content filter.
              The transport:destination syntax  is  described  in
              the  transport(5)  manual  page.   More information
              about external content filters is  in  the  Postfix
              FILTER_README file.

              Note:   this  action  overrides  the  main.cf  con-
              tent_filter  setting,  and  currently  affects  all
              recipients of the message.

              This feature is available in Postfix 2.0 and later.

       HOLD optional text...
              Place the message on the hold queue, where it  will
              sit  until someone either deletes it or releases it
              for delivery.  Log the optional text if  specified,
              otherwise log a generic message.

              Mail  that  is  placed on hold can be examined with
              the postcat(1) command, and  can  be  destroyed  or
              released with the postsuper(1) command.

              Note:  use  "postsuper -r" to release mail that was
              kept on hold for a significant fraction  of  $maxi-
              mal_queue_lifetime  or  $bounce_queue_lifetime,  or
              longer.

              Note: this action currently affects all  recipients
              of the message.

              This feature is available in Postfix 2.0 and later.

       PREPEND headername: headervalue
              Prepend the specified message header  to  the  mes-
              sage.  When this action is used multiple times, the
              first prepended header appears  before  the  second
              etc. prepended header.

              Note:  this action does not support multi-line mes-
              sage headers.

              Note: this action must be used before  the  message
              content   is   received;   it  cannot  be  used  in
              smtpd_end_of_data_restrictions.

              This feature is available in Postfix 2.1 and later.

       REDIRECT [email protected]
              After  the  message  is queued, send the message to
              the  specified  address  instead  of  the  intended
              recipient(s).

              Note:  this action overrides the FILTER action, and
              currently affects all recipients of the message.

              This feature is available in Postfix 2.1 and later.

       WARN optional text...
              Log a warning with the optional text, together with
              client information and  if  available,  with  helo,
              sender, recipient and protocol information.

              This feature is available in Postfix 2.1 and later.

ENHANCED STATUS CODES
       Postfix version 2.3  and  later  support  enhanced  status
       codes  as  defined  in  RFC 3463.  When an enhanced status
       code is specified in an access table,  it  is  subject  to
       modification.  The  following  transformations  are needed
       when the same access  table  is  used  for  client,  helo,
       sender,  or  recipient  access  restrictions;  they happen
       regardless of whether Postfix replies to a MAIL FROM, RCPT
       TO or other SMTP command.

       o      When  a sender address matches a REJECT action, the
              Postfix SMTP server will transform a recipient  DSN
              status  (e.g.,  4.1.1-4.1.6) into the corresponding
              sender DSN status, and vice versa.

       o      When  non-address  information  matches  a   REJECT
              action  (such  as  the HELO command argument or the
              client hostname/address), the Postfix  SMTP  server
              will  transform  a  sender  or recipient DSN status
              into  a  generic  non-address  DSN  status   (e.g.,
              4.0.0).

REGULAR EXPRESSION TABLES
       This  section  describes how the table lookups change when
       the table is given in the form of regular expressions. For
       a  description  of regular expression lookup table syntax,
       see regexp_table(5) or pcre_table(5).

       Each pattern is a regular expression that  is  applied  to
       the entire string being looked up. Depending on the appli-
       cation, that string  is  an  entire  client  hostname,  an
       entire client IP address, or an entire mail address. Thus,
       no  parent  domain  or  parent  network  search  is  done,
       [email protected]  mail  addresses  are not broken up into their
       [email protected] and domain constituent parts, nor is user+foo broken
       up into user and foo.

       Patterns  are applied in the order as specified in the ta-
       ble, until a pattern is  found  that  matches  the  search
       string.

       Actions  are  the  same as with indexed file lookups, with
       the additional feature that parenthesized substrings  from
       the pattern can be interpolated as $1, $2 and so on.

TCP-BASED TABLES
       This  section  describes how the table lookups change when
       lookups are directed to a TCP-based server. For a descrip-
       tion of the TCP client/server lookup protocol, see tcp_ta-
       ble(5).  This feature is not available up to and including
       Postfix version 2.3.

       Each  lookup  operation uses the entire query string once.
       Depending on the application, that  string  is  an  entire
       client hostname, an entire client IP address, or an entire
       mail address.  Thus, no parent domain  or  parent  network
       search  is done, [email protected] mail addresses are not broken
       up into their [email protected] and domain constituent parts,  nor  is
       user+foo broken up into user and foo.

       Actions are the same as with indexed file lookups.

EXAMPLE
       The  following  example  uses an indexed file, so that the
       order of table entries does not matter. The  example  per-
       mits  access  by the client at address 1.2.3.4 but rejects
       all other clients in 1.2.3.0/24. Instead  of  hash  lookup
       tables,  some  systems use dbm.  Use the command "postconf
       -m" to find out what lookup  tables  Postfix  supports  on
       your system.

       /etc/postfix/main.cf:
           smtpd_client_restrictions =
               check_client_access hash:/etc/postfix/access

       /etc/postfix/access:
           1.2.3   REJECT
           1.2.3.4 OK

       Execute the command "postmap /etc/postfix/access" after
       editing the file.

BUGS
       The  table format does not understand quoting conventions.

SEE ALSO
       postmap(1), Postfix lookup table manager
       smtpd(8), SMTP server
       postconf(5), configuration parameters
       transport(5), transport:nexthop syntax

README FILES
       SMTPD_ACCESS_README, built-in SMTP server access control
       DATABASE_README, Postfix lookup table overview

LICENSE
       The  Secure  Mailer  license must be distributed with this
       software.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

                                                                     ACCESS(5)